The fortified blackcurrant juice also had three times the levels of phenolic acids of normal blackcurrant juice, according to results published in the Journal of Functional Foods .
Led by scientists from the University of Eastern Finland, the researchers tested the beverages in healthy subjects and found that the fortified juice produced higher levels of metabolites in the urine, indicating good bioavailability.
“Compared to the basic blackcurrant juice, the fortified juice elicited slightly attenuated but prolonged glucose and insulin responses [when consumed by the 13 healthy adults],” wrote the researchers.
“The fortified juice had a higher level of anthocyanins and other polyphenols, and the intake of polyphenols was almost double compared to the basic juice.
“Therefore, it is conceivable that the polyphenols may have reduced or delayed the digestion of sucrose and/or the absorption of glucose.”
Functional beverage growth
The research is of particular interest to food and beverage companies as the functional beverage market continues to grow, said the researchers.
According to Datamonitor, the global functional drinks market is predicted to hit $62 billion in 2015, an increase of 29% from 2010.
While blackcurrants (Ribes nigrum) are already extensively used in juices, the researchers note that the anthocyanin content is reportedly sensitive to degradation during processing.
“Consequently, introducing additional anthocyanins into blackcurrant products from other sources is one strategy to maintain and/or increase health beneficial properties in blackcurrant juices and other products,” they explained.
In this new study, the considered the potential of crowberry (Empetrum nigrum) to fortify blackcurrant juice, since crowberry is said to have high levels of different anthocyanins, and an interesting profile of proanthocyanidins and flavonols
When tested in 13 healthy adults, the researchers found that the shapes of the curves for insulin and glucose response were different for the two juices.
Specifically, the fortified juice “slightly attenuated and sustained plasma glucose and insulin responses”.
“Our data show that adding crowberry containing different types of polyphenols into blackcurrant juice doubled the polyphenol content and improved postprandial glycemic control in healthy subjects,” wrote the researchers.
“On this basis, there are clearly several directions that food and drink producers can follow to enhance product polyphenol content to influence obesity-related metabolic diseases.”
Source: Journal of Functional Foods
Published online ahead of print, doi: 10.1016/j.jff.2012.05.001
“Fortification of blackcurrant juice with crowberry: Impact on polyphenol composition, urinary phenolic metabolites, and postprandial glycemic response in healthy subjects”
Authors: R. Torronen, G.J. McDougall, G. Dobson, D. Stewart, J. Hellstrom, P. Mattila, J-M. Pihlava, A. Koskela, R. Karjalainen